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Having trouble meeting PBS specs
I’ve been working with our local PBS affiliate sending them a monthly show that we create and deliver on DVD for the past few years. Recently they requested that we send them the episodes as a video file instead of a DVD and I’m having trouble figuring out how to create a file that meets their specs. We are shooting on Panasonic HMC150 cameras in AVCHD 1080 60i and editing in Premiere Pro CC 2014. Here are the specs that the station sent me:
HD FILE
Video Format: 1080i, 29.97 frames/sec (59.94 fields/sec) HD
File Format(s): XDCAM 1080i/60• XDCAM HQ: 4:2:0 at 35 Mbps MXF (OP1A, self contained)
• XDCAM HD422: 4:2:2, at 50 Mbps MXF (OP1A, self contained)
• Video Codec: MPEG-2 Long GOP, Sony XDCAM compliant
• Field Order: Upper field first
• Audio Format: 48 KHz sample rate, uncompressed
• Reference Tone: -20dBfs
• Operating Level: Peak program levels at -12 to -8 dBfs, nominal –10dBfs
• When a VU weighted meter is calibrated so -20 dBfs tone is 0 VU, program peaks should average 0 VU as well.I can easily using AME to set the codec, container, field order, and audio format. However, I don’t know what they mean by Reference Tone, Operating Level, and the last sentence about “a VU weighted meter”. Can someone please help me to understand how I can meet these last three requirements? I would prefer not having to ask them since they are extremely busy so I hope I can get some assistance on here.
Thanks!
Mike Silverman
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4 Replies
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Those last few sound like mix specs, not delivery format specs.
I normally ignore that stuff and pass it off to the mixer. You can set those in ProTools I assume. -
[Mike Silverman] “• Reference Tone: -20dBfs”
That’s the audio you hear when you play color bars. It used to be the thing that played on late night TV back in the 80’s and 90’s, before they started round the clock programming. Typically, before a programe starts, you have 1 min of BARS & TONE…color bars and reference tone. And that tone needs to play at -20dB.
[Mike Silverman] “• Operating Level: Peak program levels at -12 to -8 dBfs, nominal –10dBfs”
Something your audio mixer needs to address. If you have no mixer, then you address. Your audio levels need to fall between 12dB and -8dB…not peaking above -8dB. and hovering around -10dB. -12 is the low end, -8 is the high end. Don’t know how to maintain this? Hire an audio mixer.
[Mike Silverman] “• When a VU weighted meter is calibrated so -20 dBfs tone is 0 VU, program peaks should average 0 VU as well. “
Another audio note. One that I don’t quite know, as my shows are 99% mixed by audio professionals. If it goes to air, an audio mixing professional needs to be involved.
Shane
Little Frog Post
Read my blog, Little Frog in High Def -
A VU weighted meter is basically an analog meter. If you remember in the analog days, 0 VU was ideal but you still had a 10-12db pad before distortion or until audio went in the red.
With digital audio, anything over 0 is clipped and will sound distorted. So that is why -20 is kind of the new 0 VU and why they want peaking to not exceed the -12 to -8 range.
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Thanks to everyone who replied 🙂 I think I will need to have a talk with the producer to see if she will hire someone else to mix the audio. I’d love to learn how to do all of this but I can foresee it taking quite a bit of time and lots of trial and error.
Mike
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